background
block
bolt
closeup
connect
connection
construction
design
engineering
equipment
facility
flange
gas
gasoline
gray
hardware
horizontal
industrial
industry
iron
joint
manufacturing
metal
metallic
nobody
nut
object
old
part
pipe
pipeline
piping
plant
pressure
rusty
screw
shiny
stainless
steel
stud
supply
system
technology
thread
togetherness
tool
tube
valve
vessel
work